JPS61205938A - Preparation of mask - Google Patents

Abstract

PURPOSE:To directly form a mask high in precision on a glass base plate with out using a intermediate material by irradiating ionized corpuscles through a mask original on the plate to transfer the pattern, and forming discolored parts on the base plate. CONSTITUTION:Electron beams 12 are cast on a target from an electron gun 11, and radiated X-rays 14 are projected through the mask original 18 on the mask glass base plate 19 to transfer its pattern 18a and to form discolored parts 19a in the plate 19 intruded into the inside of the plate 19, having no fear of being damaged or deformed, thus permitting the base plate to be directly exposed to light to form the mask, and accordingly, the mask high in precision to be prepared.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device, and more specifically, to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device, the present invention relates to a method for manufacturing a semiconductor device, and more specifically, to a method for manufacturing a semiconductor device.
The present invention relates to a method of manufacturing a fine pattern mask for exposure by irradiating with an ion beam or the like.

[Conventional technology]

Traditionally, masks were made using the following process. First, a thin metal film that does not transmit light, such as chromium, chromium oxide, or iron oxide, is deposited on a glass substrate, and a photoresist (hereinafter referred to as resist) is coated on this metal thin film. Next, the photoresist is exposed to light through a mask original plate on which a desired pattern is formed, and developed to obtain a resist pattern. Next, using this resist pattern as a mask, the metal thin film is etched to produce a mask having the same pattern as the mask original, and the resist coated on, for example, a wafer is exposed with the thus produced mask.

[Problem that the invention seeks to solve]

The production of the above-mentioned mask involves multilayer pattern processing using a resist layer, which requires a large number of steps.In addition, from a structural perspective, there is a layer of metal film pattern provided on the mask master plate on one side, and a metal film pattern layer on the other side. There are two layers, a metal thin film and a resist film, on a glass substrate, and such a multilayer structure has the problem of causing partial pattern defects.

The multilayer structure described above is related to the resolution of the exposure device, but for example, when the pattern width of the wiring layer was conventionally about 2 μm, the resolution in the two-layer structure described above was not much of a problem.However, recently, In order to increase the degree of integration of integrated circuits, patterns have become finer, and, taking the wiring layer as an example, wiring patterns with submicron widths have become required.Therefore, resist masks are exposed using electron beams. The patterns used at this time must be minute and accurate.In mask manufacturing, improvements have been made to resists and exposure equipment in order to form patterns with a width of about 1 μm. However, unlike conventional methods, the present invention aims to provide a mask manufacturing method that does not use resist.

Further, in the manufactured mask, the pattern is formed of a metal layer, and there is also a problem of pattern deformation due to stress in the metal layer due to differences in thermal expansion coefficients between the metal and the glass substrate.

[Means for Solving the Problems] The present invention provides a method for manufacturing a mask that solves the above-mentioned problems. The mask manufacturing method is characterized in that a pattern of a mask original is transferred and a discolored portion is formed in the substrate.

[Effect]

The above method utilizes the fact that when a material other than quartz glass, such as aluminoborosilicate glass, is irradiated with a high-energy beam, the glass surface becomes colored and becomes opaque to light.
Since a mask is formed by directly exposing a substrate made of the material to light using charged particles, there is no intermediate material such as a resist, and the mask can be manufactured with high precision.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

To form a mask by the method of the invention, for example, the first
It is preferable to use the apparatus shown in the side view of the figure, in which 11 is an electron gun, 12 is an electron beam, 13 is a tungsten (W) target, 14 is an X-ray emitted from the target 2, and 15 is an X-ray A housing, 16 a vacuum pump, 17 a motor, 18 a mask original, and 19 a glass substrate are shown, respectively. (Electronic Materials Special Issue: Featured Fundamental Technologies of VLSI, 69
From the following pages, Teruo Shirai, X-ray transfer device. ) The mask master plate 18 used in the above apparatus is a gold (Au) mask, and its support layer is made of Mylar. The mask to which the X-rays are irradiated is a clean polysilicate glass, for example an aluminoborosilicate glass substrate. The mask original plate and the glass substrate are placed in close contact with each other or with a predetermined distance between them, but which method is used depends on the mask pattern,
Select as appropriate, taking into consideration the dimensions of the mask, etc. Note that quartz glass does not change color even when irradiated with X-rays, so quartz glass cannot be used as a substrate in the present invention.

To obtain X-rays, the W target was irradiated with an electron beam having an acceleration energy of 50 KeV. When the mask was inspected after being irradiated with X-rays for about 20 minutes, a brownish-colored pattern was obtained that was a transfer of the original, and the optical density (OD) of this pattern was 2.0 or more at λ = 4000 people. It was confirmed that it can be used as a mask. Furthermore, since such patterns were drawn using X-rays, fine patterns were accurately formed. Since the pattern is formed within the substrate, it will not be deformed or destroyed.
It is understood that the coloring of the substrate by X-ray irradiation does not involve a chemical change. It was also confirmed that the colored pattern on the substrate did not change over time and could withstand repeated use as a photomask.

FIG. 2 is a partial cross-sectional view of the mask original plate 18 and the glass substrate 19, in which a sandy area 18a shows a pattern, and a hatched area 19a shows a discolored pattern.

As can be understood from the figure, the discolored part is embedded in the glass substrate and does not protrude above the glass substrate like a metal pattern, so there is no risk of damage or deformation of the pattern. and such a pattern is
It has been confirmed that the patterns of the present invention can be formed not only by wires but also by electron beams (EB), that is, the patterns of the present invention are generally formed by charged particles.

〔Effect of the invention〕

As explained above, according to the present invention, X-rays, EB.

Since a fine pattern for a mask is directly formed on a substrate using a method such as the above, it is highly effective in improving the yield and reliability of mask manufacturing.

[Brief explanation of drawings]

FIG. 1 is a layout diagram of a system used to carry out the method of the present invention, and FIG. 2 is a sectional view showing a pattern of a mask made by the method of the present invention. In the figure, 11 is an electron gun, 12 is an electron beam, 13 is a target, 14 is an X-ray, 15 is an X-ray source housing, 16 is a vacuum pump, 17 is a motor, 18 is a mask original, 19 is a mask, are shown respectively. Figure 1 @ Figure 2

Claims (1)

[Claims] 1. A method for manufacturing a mask, which comprises irradiating charged particles onto polysilicate glass serving as a mask substrate through a mask original plate, transferring a pattern of the mask original plate, and forming a discolored portion in the substrate.